Switching means for button clamp on sewing machines for sewing on of buttons



Dec. 13, 1960 o. BRAUN ETAL 2,963,999

SWITCHING MEANS FOR BUTTON CLAMP ON SEWING MACHINES FOR SEWING ON 0F BUTTONS Filed Dec. 26, 1957 2 Sheets-Sheet 1 INVENTO/P5 Dec. 13, 1960 2,963,999

0. BRAUN ETAL SWITCHING MEANS FOR BUTTON CLAMP ON SEWING MACHINES FOR SEWING ON OF BUTTONS Filed Dec. 26, 1957 2 Sheets-Sheet 2 F/G. 3 6E r, W INVENTOPS United States Fatent 55 25%3399 Fatented Dec. 13, 1960 SWITCHING MEANS FOR BUTTON CLAMP ON glgvlglsNG IVIACHINES FOR SEWING ON OF BUT- Oskar Braun and Karl Winz, both of KaiserslautermPfalz, Germany, assignors to G. M. Pfaif AG., Kaiserslautern, Pfalz, Germany Filed Dec. 26, 1957, Ser. No. 705,284

Claims priority, application Germany Jan. 22, 1957 6 Claims. (Cl. 112-76) The invention relates to the guiding control of the button clamp on sewing machines for sewing on eyelet and other buttons, where a block is provided on the housing to control the opening and closing movements of the button clamp.

In all of the known guiding systems of this type the opening and closing movement, controlled by an abutment, coincides with the lifting and lowering of the button clamp. In the case of one of the known control systerns, the clamp is automatically raised after a complete sewing operation in that the clamp is coupled with a moving component of the machine. In another known system the clamp is lifted as a spring'is released. Finally, there already exists an electromagnetic guiding control system. Here, the clamp is raised by pulling means, actuated at the completion of the sewing operation by the armature of an electromagnet. The finished work material can be removed immediately after the lifting of the clamp and a new button can be inserted into the clamp which opens while being raised.

In the case of the known systems, the seamstress must hold the button guided between the jaws of the clamp in her hand, until a firm grasp has been established by the closing clamp jaws. The coupling of the sewing machine to the motor can take place only after the clamp has been completely lowered on the stitch plate. A system of locking gear is provided for the purpose of blocking the clutch lever during the time the clamp is in raised position. If the seamstress does not release the button immediately when the operating position is reached there is a danger of the seamstress being wounded as a result of accidental coupling.

It is an object of this invention to prevent that the closing and lowering phases of the button clamp coincide. The possibility is to be created of closing the clamp in its raised position without the necessity of moving it at the same time so that the lowering will not hamper the insertion of the button. In accordance with the invention this is achieved by a releasable locking system which holds an abutment in operating position which is movable into the path of movement of the clamp operating lever.

A particularly effective embodiment of this release comprises a two armed or toggle articulated lever having an arm connected with the abutment which is shorter than the one mounted on the operating shaft so that even a small force applied to the release lever causes release of the abutment from its locked position and its shifting into operating position. Thus, only a short impulse is necessary to move both arms of the toggle levers from their locking condition by that small amount beyond fully stretched position which is required to cause shifting of the abutment under the pressure exerted on the abutment of the clamp operating lever.

The block returns into its operating position by its own weight after the lowering of the clamp. The movement is supported by a resetting spring which moves the block into its operating position and at the same time forces the articulated lever against a stop placed in its path of movement.

Further objects and advantageous features. of this invention become apparent on the enclosed drawing which illustrate one embodiment of the invention and in which Fig. 1' is a side elevational view of a machine for sewing on buttons provided with the switching mechanism.

Fig. 2 is a partial side elevational view of the machine drawn to an enlarged scale with the clamp in raised and opened position.

Fig. 3 is the same partial view, with the clamp closed in raised position.

Fig. 4 is another partial view in accordance with Figs. 2' and 3, but with the clamp lowered ontothe stitch plate.

The essential components of the machine for sewing on buttons comprise base 2., standard 3, arm. 4, head 5 and supporting arm 6. The main shaft (not shown) is journalled inarm 4 and drives the looper shaft and auxiliary looper shaft mounted in the supporting arm by Way of known connecting members such as bevel gears, drive shafts, etc. The main shaft in turn is connected by coupling 8 and drive belt 7 with the motor located under the table top. Coupling 8 comprises in a known manner the idler disc 11 and balance wheel 12 rigidly secured to the main shaft. Belt 7 can be shifted from idler disc 11 to balance wheel 12 by means of brake switch lever 13 rotatably'mounted on a standard 3 and supporting the belt guiding means 14. Shifting lever 13 for coupling and brake which is in the form of a bell crank lever extends with its one arm 15- into the path of movement of switch lever 61-, which is pivotally mounted on base 2 and which is rockable in a known manner by way of foot pedal and provides the coupling of the motor with the main shaft, releasing at the same time the mechanical brake.

The deflection of the needle bar and of the feed movement of button clamp 19 are guided in a known manner by cam 10. In addition, shifting lever 13 of coupling 8' is actuated in a known manner by the project-ions of cam disc it and after the termination of a sewing operation shifts belt 7 by means of belt guide 14 from dri ve wheel-12 onto idler disc 11 while simultaneously braking the drive wheel.

The lower extremity of lifting lever 9 glided with its axis parallel to the needle bar has a square end portion 16 to which is secured lifting member 18 for button clamp 19 by means of a screw 17. One end of a lever block 2% is mounted on lifting bar 9 inside head 5 while its other end 21 extends through slot 22 in the dome shaped wall of head 5. The end 21 is held in guide member 23- which in turn is fastened by screws 24' to arm 4, thus limiting the vertical movement of lifting lever 9 and preventing rotary movement. The end 21 of lever block 29 located externall-y of head 5 carries draw bar ZS'mounted thereon by screw 25:: and receiving pin 26 in its upper end. Pressure spring 27, concentric with bar 9, which normally depresses said bar, is biased against lever block 29 on bar 9-" and against the wall of head 5. Said spring 27 is compressed by the forcible upward movement of bar 9;

The end opposite the fastened end of lifting member 18' is enlarged and contains a slot- ZZiz; Connecting link 29, secured with two screws 30 on top of button clamp 19 is movable in slot 27a by means of screw 23. Button clamp 19 is rockable upwardly about pivot member 35 located on supporting arm 6 of the machine and comprises the following components: fixed jaw 31, jaw 32 movable axially of the block axis and jaw 33 movable vertically with respect to jaw 32. While in position of rest, both movable jawsare pressed together by spring 34 which acts on their sliding members firmly holding the button inserted between the jaws. When pnll rod 25 is. raised,

button clamp 19 1s moved upwardly about pivot member 35 by means of lifting bar 9. A control mechanism of known design between button clamp 19 and cam disc '10 permits'axial'displacement of the entire button clamp 19 in coordination with the sequence of sewing operations.

Actuating pin 37, cooperating with link 36 can be shifted in a slot of clamp 19 against the pressure of spring 34 which is directed against said link 36 of the two movable jaws 32 and 33. Angular lever 40, mounted on raised wall portion 39 of clamp 19 by means of screw 38 engages actuating pin 37 with its claw-shaped arm 41. Set screw 43 defining a contact member secured by lock nut 44 is secured to second arm 42 of lever 40. When pressure is applied against set screw 43, angular lever 40, hereafter referred to as clamp operating lever 40, is rocked clockwise, while the power is transmitted by way of actuating pin 37 to spring 34 as clamp jaws 32, 33 shift and open clamp 19.

Clamping devices suitable for use in combination with the guiding means disclosed herein and operating in a manner similar to the clamping mechanism illustrated by Way of example are well known in the art. For example the clamping mechanisms illustrated in US. Patents Nos. 1,354,794 and 2,359,035 are of that type. Particularly the mechanism in accordance with Patent 2,359,035 can be readily used in combination with the guiding means in accordance with the present invention.

A bracket 46 is mounted by two screws 45 on head 5. An abutment member 47 has one end attached to bracket 46 by means of pin 53, while its other end is pivotally connected to one end of the short arm 48 of a two armed toggle joint 49.

The second, long arm 51 of toggle joint lever 49 is connected at its end remote from the collapsible joint 50 to operating pivot shaft 52. Said pivot shaft 52 is journalled in support 46 at a constant distance from pivot point 53 of block 47 and parallel to its axis of rotation. Pivot shaft 52 also carries a trip lever 54 for toggle lever 49. The angle formed by trip lever 54 and lever arm 51 is constant; consequently when there is a clockwise pressure on trip lever 54, lever 49 is displaced while long lever arm 51 becomes fully effective in this transmission of power.

Abutment 47 is moved into its operating position when button clamp 19 (Fig. 4) is lowered and clamp operating lever 40 with set screw 43 do not protrude into the path of movement of said block. The path of movement of toggle lever 49 in the direction of abutment 47 and beyond its stretched position is limited by stop 55. (Fig. 2.) Set screw 56 provides the possibility of selecting the optimum value at which the blocking effect occurs when pressure is exerted on abutment 47. Armature 58 of release magnet 57 applies a rotating movement to trip lever 54 when the magnet is energized; as previously described, this movement rocks toggle lever 49 as the locked condition is removed. Armature 58 is kept out of the range of movement of trip lever 54 by pressure spring 59 when the magnet is not energized. The return of abutment 47 to its operating position is effected by its own weight and is supported by a restoring spring 60 which is disposed around pin 53 and rests with its arm 60a against abutment 47, while the other arm 60b rests against support 46.

Raising of lifting lever 9 and also of button clamp 19 which is connected thereto is effected by lift lever 62 which reaches under pin 26 of draw bar 25 and is rotatably mounted on pivot member 63 on arm 4. The shorter arm 64 of lift lever 62 engages pin 26, while the end of its longer arm 65 is connected with the foot pedal (not shown) by way of link 66 andcoupling chain 67. A stud 68 is inserted on the extreme end of arm 65. Safety catch 69, rotatable on pivot 70, hinges on housing 4 underneath stud 68; the upper end of said safety catch has a recess 71 which corresponds to the path of movement followed by bolt 68 during rotation of release lever 62. The other end of safety catch 69 is connected to one end of connecting bar 73 by way of shoulder screw 72 while the other end of said bar is pivotally mounted on shifting lever 13.

As long as there is noiforce applied by Way of coupling chain 67 on leyerrarm 65 of release lever 62, the latter is pulled clockwise to the end of its path of movement by pull spring 75, attached at one end on release lever 62 and at the other end to the wall of head 5.

The operation of the new switching mechanism is as follows:

After cutting in the motor, drive belt 7 runs on idler disc 11. Button clamp 19 is lifted by coupling chain 67 and is opened when clamp operating lever 40 engages abutment 47 which is locked in its operating position by toggle lever 49. (See Fig. 2.) A button can now be inserted between the open jaws of 31-33 of clamp 19. When this has happened magnet 57 is energized by operating a switch of any suitable type (not shown) to supply current to the coil of the magnet. Upon excitation of magnet 57 armature 58 strikes against trip lever 54 and rocks it clockwise so that the locked condition of abutment 47 is removed. (See Fig. 3.) As a result of the pressure of clamp operating lever 40, acting on the bottom of abutment 47, the abutment rocks upwardly and the force of the resetting spring 34 acting on link 36 can now move jaws 32 and 33. The button introduced in the clamp is now firmly held. Clamp 19 is further lifted, the material to be sewn can be freely inserted and then the clamp is lowered. During the lowering phase release lever 64 is rotated clockwise around its point of rotation 63 so that lifting lever block 20 in its mounting 24 and lifting lever 9 connected thereto can slide downwardly under the effect of pressure spring 27. As the button clamp 19 moves downwardly the clamp operating lever 40 and stop screw 43 are removed from the rocking path of abutment 47 so that said block is returned under its own weight to its initial operating position, to be locked anew in that position by toggle lever 49. The movement of the block is assisted by return spring 60.

Should the seamstress, after lowering of clamp 19, find out that the position of the material to be sewn is not correct, it is possible after the excitation of release magnet 57 which removes abutment 47 from its operating position, to lift the clamp in closed condition, since clamp operating lever 40 has no effect on jaws 32 and 33 of the clamp. The new lowering takes place in the manner already described.

Upon operating operating lever 61, belt 7 is shifted from idler disc 11 to balance wheel 12 by way of belt guide 14 as operating lever 13 is shifted, while at the same time, the mechanically acting brake of balance wheel 12 is released. Operating lever 61 can be controlled mechanically from the foot pedal by means of connecting mechanism (not shown). There exists also the possibility of having the armature of an electromagnet act directly or indirectly by a pull connection on the operating lever 61.

After the completed coupling operation the entire oper-. ation takes place automatically controlled by cam disc 10. As already described, lift lever 62 moved clockwise after the lowering of the button clamp causing the lifting of longer arm 65 and sliding of stud 68 along recess 71 of safety catch 69 until stopped on the upper part of safety catch 69. Upon coupling, safety catch 69 was rotated clockwise about its pivot 70 by means of transmission bar 73 connected with shifting lever 13 as the upper edge of said safety catch moves directly underneath stud 68. Now, if a force is applied by way of lift chain 67 on release lever 62, said lever is prevented from rotating counter-clockwise, since stud 68 strikes against safety catch 69 causing it to rock and is thus not able to slide into recess 71. Consequently this stop is a safety measure against the lifting of button clamp 19 anemone during the course of a sewing operation. If the sewing machine is stopped automatically by conformations on cam disc which act on switch lever 61 then safety catch 69 is tilted counter-clockwise to a position which permits the upward sliding of stud 68 in recess 71 so that the renewed raising of button clamp 19 is possible, after the machine has been brought to a stop. Since there normally is no excitation of operating magnet 57 and block 47 is therefore locked in its operating position, lifting the clamp 19 simultaneously opens the same as described so that the finished material can be removed and a new button can be inserted in the clamp. All further movements are analogous to those described.

Since in mounting of the operating shaft care must be taken that it is placed at a constant distance from the pivot point and parallel to the axis of rotation of the abutment there exists the possibility on one hand, in the case of production assembly to hinge the abutment and control pivot on the housing; on the other hand, in the event of subsequent mounting, the abutment and control shaft can be provided on a bracket which in turn is mounted on the housing.

Having now described our invention with reference to the embodiment illustrated in the drawings, we claim:

1. Guiding means for the button clamp of sewing machines comprising in combination a needle bar vertically disposed in the head of the machine and adapted for sewing on eyelet and lump buttons, a button clamp having a clamp end presenting at least one movable jaw and a support end pivotally supported at said support end on the machine base and extending longitudinally of said base for rocking movement of said clamp end relative to said needle bar and having an actuating lever pivotally mounted intermediate said ends and presenting a contact member, a slidable member operatively related to said movable jaw presenting an actuating pin operatively engaged by said lever and a spring biasing said slidable member in a direction establishing the closed condition of said clamp end, an abutment member having operative engagement with said contact member mounted on the machine head in operative relation to and above said actuating lever and being operative to control the opening and closing movements of said button clamp by way of said contact member, said pin and said slidable member, and collapsible latching means including a double armed toggle joint having one arm linked to said abutment member and another arm pivotally supported proximate said machine head and operative to rock said member into operative position in the path of movement of said actuating lever.

2 Guiding means for the button clamp of sewing machines comprising in combination a needle bar vertically disposed in the head of the machine and adapted for sewing on eyelet and lump buttons, a button clamp having a clamp end presenting at least one movable jaw and a support end pivotally supported at said support end on the machine base and extending longitudinally of said base for rocking movement of said clamp end relative to said needle bar and having an actuating lever pivotally mounted intermediate said ends and presenting a contact member, a slidable member operatively related to said movable jaw presenting an actuating pin operatively engaged by said lever and a spring biasing said slidable member in a direction establishing the closed condition of said clamp end, an abutment member having operative engagement with said contact member mounted on the machine head in operative relation to and above said actuating lever and being operative to control the opening and closing movements of said button clamp by way of said contact member, said pin and said slidable member, and collapsible latching means including a double armed toggle joint having one arm linked to said abutment member and another arm pivotally supported proximate said machine head and operative to rock said member into operative position in the path of movement *3 of said actuating lever, and limiting means operatively associated with one arm of said toggle joint and with said abutment member, adapted to control the stretched condition of said toggle joint.

3. Guiding means for the button clamp of sewing machines comprising in combination a needle bar vertically disposed in the head of the machine and adapted for sewing on eyelet and lump buttons, a button clamp having a clamp end presenting at least one movable jaw and a support end pivotally supported at said support end on the machine base and extending longitudinally of said base for rocking movement of said clamp end relative to said needle bar and having an actuating lever pivotally mounted intermediate said ends and presenting a contact member, a slidable member operatively' related to said movable jaw presenting an actuating pin operatively engaged by said lever and a spring biasing said slidable member in a direction establishing the closed condition of said clamp end, an abutment member having operative engagement with said contact member mounted on the machine head in operative relation to and above said actuating lever and being operative to control the opening and closing movements of said button clamp by way of said contact member, said pin and said slidable member, and collapsible latching means including a double armed toggle joint having one arm linked to said abutment member and another arm pivotally supported proximate said machine head and operative to rock said member into operative position in the path of movement of said actuating lever, and limiting means operatively associated with one arm of said toggle joint and with said abutment member, adapted to control the stretched condition of said toggle joint, said abutment member being pivotally connected at one end to the machine head and at the other end to one arm of said toggle joint, and said toggle joint having said other said arm at its end remote from the joint of the toggle pivotally mounted upon an operating shaft at a constant distance from and parallel to the axis of rotation of said abutment member, and a toggle release lever pivotally supported at and extending from said axis of rotation of said toggle joint arm.

4. Guiding means for the button clamp of sewing m-achines comprising in combination a needle bar vertically disposed in the head of the machine and adapted for sewing on eyelet and lump buttons, 21 button clamp having a clamp and presenting at least one movable jaw and a support end pivotally supported at said support end on the machine base and extending longitudinally of said base for rocking movement of said clamp end relative to said needle bar and having an actuating lever pivotally mounted intermediate said ends and presenting a contact member, a slidable member operatively related to said movable jaw presenting an actuating pin operatively engaged by said lever and a spring biasing said slidable member in a direction establishing the closed condition of said clamp end, an abutment member having operative engagement with said contact member mounted on the machine head in operative relation to and above said actuating lever and being operative to control the opening and closing movements of said button clamp by way of said contact member, said pin and said slidable member, and collapsible latching means including a double armed toggle joint having one arm linked to said abutment member and another arm pivotally supported proximate said machine head and operative to rock said mem her into operative position in the path of movement of said actuating lever, and limiting means operatively associated with one arm of said toggle joint and with said abutment member, adapted to control the stretched condition of said toggle joint, said abutment member being pivotally connected at one end to the machine head and at the other end to one arm of said toggle joint, and said toggle joint having said other said arm at its end remote from the joint of the toggle pivotally mounted 'upon an operating shaft at a constant distance from and abutment member being shorter than said other arm of said joint.

5. Guiding means for the button clamp of sewing machines comprising in combination a needle bar vertically disposed in the head of the machine and adapted for sewing on eyelet and lump buttons, a button clamp having a clamp end presenting at least one movable jaw and a support end pivotally supported at said support end on the machine base and extending longitudinally of said base for rocking movement of said clamp end relative to said needle bar and having an actuating lever pivotally mounted intermediate said ends and presenting a contact member, a slidable member operatively related to said movable jaw presenting an actuating pin operatively engaged by said lever and a spring biasing said slidable member in a direction establishing the closed condition of said clamp end, an abutment member having operative engagement with said contact member mounted on the machine head in operative relation to and above said actuating lever and being operative to control the opening and closing movements of said button clamp by way of said contact member, said pin and said slidable member, and collapsible latching means including a double armed toggle joint having one arm linked to said abutment member and another arm pivotally supported proximate said machine head and operative to rock said member into operative position in the path of movement of said actuating lever, and limiting means operatively associated with one ann of said toggle joint and with said abutment member, adapted to control the stretched condition of said toggle joint, said abutment member being pivotally connected at one end to the machine head and at the other end to one arm of said toggle joint, and said toggle joint having said other said arm at its end remote from the joint of the toggle pivotally mounted upon an operating shaft at a constant distance from and parallel to the axis of rotation of said abutment member, and a toggle release lever pivotally supported at and extending from said axis of rotation of said toggle joint arm, said one arm of said toggle joint connected to said abutment member being shorter than said other arm of said joint, and said abutment member including a resetting spring disposed at the connection of said member to said machine head.

6. Guiding means for the button clamp of sewing machines comprising in combination a needle bar vertically disposed in the head of the machine and adapted for sewing on eyelet and lump buttons, a button clamp having a clamp end presenting at least one movable jaw and a support end pivotally supported at said support end on the machine base and extending longitudinally of said base for rocking movement of said clamp end relative to said needle bar and having an actuating lever pivotally mounted intermediate said ends and presenting a contact member, a slidable member operatively related to said movable jaw presenting an actuating pin operatively engaged by said lever and a spring biasing said slidable member in a direction establishing the closed condition of said clamp end, an abutment member having operative engagement with said contact member mounted on the machine head in operative relation to and above said actuating lever and being operative to control the opening and closing movements of said button clamp by way of said contact member, said pin and said slidable memher, and collapsible latching means including a double armed toggle joint having one arm linked to said abutment member and another arm pivotally supported proximate said machine head and operative to rock said member into operative position in the path of movement of said actuating lever, and limiting means operatively associated with one arm of said toggle joint and with said abutment member, adapted to control the stretched condition of said toggle joint, said abutment member being pivotally connected at one end to the machine head and at the other end to one arm of said toggle joint, and said toggle joint having said other said arm at its end remote from the joint of the toggle pivotally mounted upon an operating shaft at a constant distance from and parallel to the axis of rotation of said abutment member, and a toggle release lever pivotally supported at and extending from said axis of rotation of said toggle joint arm, said one arm of said toggle joint connected to said abutment member being shorter than said other arm of said joint, said abutment member including a resetting spring disposed at the connection of said member to said machine head, and said abutment member and said operating shaft being provided on a mounting secured to said housing of said machine.

References Cited in the file of this patent UNITED STATES PATENTS 

